If they're anything like my kids, the novelty will wear off pretty quickly, and you'll get your iPod back (hopefully still in one piece). Now, they usually don't request to watch TV on the iPod, in fact more often they want to listen to their audio playlists. 😛
That said, having some of their programming on the iPod has been a lifesaver in many occasions where they need to stay in one place much longer than expected. Such as the time we had to wait for an extra hour at the doctor's office before my 5 year old's (then 4) surgery. Being able to have him calm down and watch something familiar was very helpful. It's also come in handy while on the road. My 3 year old has to do breathing treatments for asthma that require him to sit still for 10-15 minutes and there isn't much kid friendly programming in hotels at night... It's hard to read to him or play a game during the treatments since he needs to sit straight and it's quite noisy, so TV provides a decent focal point.
B